Automotive bumpers must have the capability to manage impact energy without suffering excessive damage. To meet this requirement, most bumper beams have an invariant sectional configuration characterized by longitudinally invariant strength not only in bending, but also in compression and in resistance to buckling. Each of these characteristics must be sufficient to protect a vehicle against excessive damage. However, a bumper having an invariant cross section exhibiting the same bulk operational characteristics as the present inventive bumper, will weigh, and likely cost, more than the present bumper because the impact reaction of a bumper, in compression, for example, occurs primarily through the frame horns. As a result, much of the strength characterizing the entire length of a conventional, longitudinally invariant, bumper is not needed, and cannot be utilized. As a result, the unusable structure is in essence, wasted.
The present inventive bumper uses a localized, structurally modified beam substrate to react against impact loading, especially those reacted through the frame horns of a vehicle, while at the same time providing savings in material, weight, and cost.